(a) Technical Field of the Invention
The present invention generally relates to prosthetic legs, and more particularly to a knee joint for prosthetic legs which confines the bending angle within a range and absorbs the shocks during walking.
(b) Description of the Prior Art
The most important and complicated part of a prosthetic leg is the knee joint. The prosthetic knee joint not only should work like a real human joint, but also should make the user walk in a natural way.
Conventional prosthetic knee joints, as disclosed in R.O.C. Patent No. 549,074, utilize a plurality of joining elements to link a prosthetic thigh and prosthetic shin and foot. The prosthetic knee joint could imitate how a real human joint bends, and a cushion pad is configured on a lower joining element for absorbing the shock from the ground.
The drawbacks of these conventional prosthetic knee joints are as follows. The shock absorbing capability of the cushion pad is only available when the prosthetic thigh and shin are aligned in a straight line when the leg is landed on the ground. This is of no concern for a user walking on a flat ground. However, when the user is walking downhill, the prosthetic leg is bended with a small angle and the cushion pad is therefore unable to absorb the shock. In addition, the joining elements of the conventional prosthetic knee joint are unable to keep the bending of the prosthetic leg within a range. Therefore, when the user is walking on flat ground or on a slope, the shin would dangle from the knee joint when the prosthetic leg is lifted from the ground, causing the user to suddenly kneel down. Accordingly, there is a need for a better structured prosthetic knee joint that could imitate more naturally how real people walk.